International journal of behavioral medicine
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We investigated the role of conditioning experiences and response expectancies in the generation of placebo effects. On 3 sequential days (Test 1, Experimental Session, Test 2), 66 female undergraduates were presented with a series of pain stimuli. For the experimental group, placebo administration (analgesic cream) was paired with a decrease in the painful stimulus. ⋯ Mere verbal persuasion was not sufficient to elicit placebo-induced pain reduction. Irrespective of the experimental manipulations, the placebo effect was related to both reduced pain expectations and reduced fear of pain. Although conditioned placebo responses were evident at the subjective level, no placebo effects emerged at the physiological level.
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Subjective disability is considered as the variable that reflects the impact of chronic pain on a patient's life. This study examines the questions of which syndrome or patient characteristics determine subjective disability and whether there are differences between samples of patients with chronic headaches and low back pain. Direct pain variables and depression, pain coping strategies, and pain-related self-statements (including catastrophizing) are introduced into multivariate regression analyses as potential predictors of disability using a sample of 151 pain patients. ⋯ In this study, we present a critical analysis of possible interpretations of our results. We point to an overlap of concepts underlying some of the variables used: this overlap also considerably invalidates conclusions drawn from a multitude of studies done in this field, including the one presented. We strongly argue for a conceptual clarification, and consequently for the revision of assessment instruments, before further empirical work in this area is done.